DNS for private network

I have 10 systems in our network, I have assigned static IP(private IP) for all systems manually. There is a web server running in our network with private IP say 192.168.2.15. What I want is instead of type http://192.168.2.15 in browser and access webserver, everyone(only LAN users) should use a name say http://mydomain.com or http://mydomain.local in browser. How do I do this with mikrotik router 750GL?

NOTE: the domain shouldn’t be accessible from outside LAN.

all the device must have as DNS the ip of RB750,
enable DNS and configure it correctly on RB750,
create one static entry on that DNS.
Done.

How do I enable dns in mikrotik router? this is the dns settings which is already exists.

[niren@MikroTik] > ip dns print

servers: 202.83.21.12,202.83.20.101
dynamic-servers:
allow-remote-requests: yes
max-udp-packet-size: 4096
cache-size: 2048KiB
cache-max-ttl: 1w
cache-used: 21KiB

and then no idea about create a static entry.

http://wiki.mikrotik.com/wiki/Manual:IP/DNS#Static_DNS_Entries

This is what I tried as per the link shown above.

[niren@MikroTik] /ip dns static> print                                     
Flags: D - dynamic, X - disabled, R - regexp 
 #     NAME         ADDRESS                                        TTL         
 0     mysite.com 192.168.2.14                                   1d

and dns servers is

[niren@MikroTik] /ip dns> print
                servers: 202.83.21.12,202.83.20.101
        dynamic-servers: 
  allow-remote-requests: yes
    max-udp-packet-size: 4096
             cache-size: 2048KiB
          cache-max-ttl: 1w
             cache-used: 81KiB

In my local system:

niren@hammett:~$ nmcli dev list iface eth0 | grep IP4
IP4.ADDRESS[1]:                         ip = 192.168.2.4/24, gw = 192.168.2.1
IP4.DNS[1]:                             192.168.2.1
IP4.DNS[2]:                             202.83.21.12

192.168.2.1 is router address for LAN users.

Tests I did:

niren@hammett:~$ ping mysite.com
ping: unknown host mysite.com

niren@hammett:~$ traceroute mysite.com
mysite.com: Name or service not known
Cannot handle "host" cmdline arg `mysite.com` on position 1 (argc 1)

Set only one dns server address in your computer: the router.